Heat-treating furnace



BEST AVMLI'RBLECOP.

Feb. 15, 1927.

A. D. KEENE HEAT TREATING FURNACE Filed Oct. 15, 1923 INVENTOR A /1 D. Keene,

WITNESSES: fiia;

ATTORNEY BEST AVAILABLE COP.

Patented Feb. 15, 1927.

UNITED STATES PATENT OFFICE.

ALVIN D. KEENE, or rrrrsnuaon, rENNsYLvANIa, assrouon ro wEsrINGIIoU'sE amo rmo & MANUFACTURING COMPANY, A CORPORATION or PENNSYLVANIA.-

HEAT TREATING FURNACE.

Myinvention relates to electric furnaces and particularly to high temperature elec-- tric furnaces for heat-treating metal objects. One object of my invention is to provide an electric furnace of relatively simple and compact construction that shall have a her source of relatively high temperature.

Another object of my invention is to providean electric furnace comprising a heating chamber and a resistor located entirely within a single refractory member.

In practicing my invention, I provide a tor member having a hcattreating chamber and one or more heating chambers within each of which there is located a resistor to provide the necessary heat.

In the single sheet of drawings, Figure 1 is ayiew, in vertical longitudinal section, of an electric furnace embody- '-in my invention, and

igs Z is a top plan view of a refractory mem r embodying the heat treating and the; heating chambers.

fu'rnace structure 11 comprises an outer casin '12 that may be. built up of suitable heatsulatin refractory material, either in the form of bricks or blocks or of a mass of such material. An .inner lining 13 is provided within the outer casing 12 and. it

' cross-section.

comprises either a unitary mass or a plurality of bricks or blocks of asuitable hightemperature resisting refractory material usually employed in the art.

A cover member for the furnace structure comprises an outer casing 15 of substantially the same construction as the casing 12 and an inner lining 16 of substantially the same construction as the inner lining 13. This cover member is made removable from the rest of the furnace structure to permit of easy access to a chamber 17 that is located within the inner lining 13.

'A carborundum lining 18 is provided within .the chamber 17 and it has located therein asingle block of refractory eiectricconducting material 19. The block 19 may be made of carbon or graphite and, as illustrated in the drawings. is of substantially rectangular contour in longitudinal section and. may be of either square or rectangular The block 19 is provided with a central lateral chamber 21 and with a plurality of lateral chambers22 and 23 located ad acen t to the ends of the block 19.

Elongated carbonaceous electrodes 24 extend through suitable openings 25 in the cover portion of the furnace and into the respective chambers and 23. Means for uljustably supporting the respective elec-' trodes 2i comprise screw'threaded, vertically extending rods or shafts 26 having a supporting means 27 mounted on the cover member and provided with hand-wheels 28 at their upper ends. holds the respective electrodes 24in their proper operative position relatively to the block 19, substantially as illustrated in Fig.

l of the drawings, and. permits of varying the position thereof when required.

Supply circuit conductors (not shown) are electrically connected to the electrodes 24: and an electric current traverses the two electrodes and the block 19 in series circuit relation, an are being formed between the electrodes and the block within-the two chambers 22 and 23.- This type of heatin element has been moreparticularly described and claimed in my co-pending application,

Serial No. 658,031, filed August 18, 1923,

and assigned to the \Vestinghouse Electric & Manutacturing Company, to whichapplication reference may be had for further details-of construction and of operatioin of this type of furnace.

In general, itmay be here noted that any are formed occurs between the end of the electrode and the block 19 at substantially the bottom of the chamber 2:2 or 28, whereby a substantially protect-ed are is provided and such are will operate for a relatively long period of time without necessitating an adjustment of the elongated electrode 24.

The temperature of the are is relatively ver}? high but there is a. relatirialydarge temperature gradient. between the heating chambers 22 and 23 and the work-receiving chamher or compartment 21, and adjustment of the position of the electrodes makes it pos- A clamping means 29 sible to obtain substantially any desired teni- BESTAVAILABLECOP:

l protect the carbonaceous material of the lock 19 against oxidation. Protecting bushings 33, of carborundlun, May be located above the heating chambers b 22 and 23to aid in protecting the electrodes 24 and the outer end portions of the block 19., i I 1 wvhere a relatively large number of elongated metal objects of one shapdor form are luto be heat treated, such as for. instance, drill hits, a furnace of the hereinbefore described t pe is very effective. As theteniperature of atumwithinrelatively small limits of variat 6 heat source is'relatively very high and i q permits of maintaining the desired tempertion and without making too great demands upon the operators time for adjusting the electrodes.

Various modifications and changes may be made herein without departing from the An electric furnace comprising a single block of refractory electric-conducting material having a plurality of spaced and laterally extending openings therein, the intermediate opening constituting a heating chamber, an elongated'eloctrode extending into each oi said outer openings and 00- operating with the walls thereof to produce an arc and a refractory high-temperature resisting casing material. i

In testimony whereof, I have hereunto surrounding said block of p subscribedniy name this 9th day of October,

ALVIN D. KEENE; 

